FIELD OF INVENTION
[0001] The present invention relates to a 3D printing apparatus.
[0002] More particularly, the present invention relates to a 3D apparatus adapted for manufacturing
objects at high speed.
BACKGROUND ART
[0003] Three-dimensional (3D) printed parts result in a physical object being fabricated
from a 3D digital image by laying down consecutive thin layers of material.
[0004] Typically these 3D printed parts can be made by a variety of means, such as selective
laser melting or sintering, which operate by having a powder bed onto which an energy
beam is projected to melt the top layer of the powder bed so that it welds onto a
substrate or a substratum. This melting process is repeated to add additional layers
to the substratum to incrementally build up the part until completely fabricated.
[0005] These printing methods are significantly time consuming to perform and it may take
several days, or weeks, to fabricate a reasonable sized object. The problem is compounded
for complex objects comprising intricate component parts. This substantially reduces
the utility of 3D printers and is one of the key barriers currently impeding large-scale
adoption of 3D printing by consumers and in industry.
Examples of known 3D printing devices include those described in US patent publication
US 2013/0108726 A1, and European patent specification
EP 2583774 B1.
US 2013/0108726 A1 discloses a means to produce a three-dimensional component by applying successive
layers of curable material onto a substrate and selectively curing regions of each
successive layer so that the cured portions of consecutive layers of material produce
the three-dimensional product.
EP2583774 B1 discloses a means to relieve stress within a part created during manufacturing of
a 3D printed product. The specification further discloses an energy beam being used
to melt layers of powdered metal to form a desired part.
[0006] The present invention attempts to overcome, at least in part, the aforementioned
disadvantages of previous 3D printing devices.
SUMMARY OF THE INVENTION
[0007] In accordance with one aspect of the present invention, there is provided a printing
apparatus for printing a three-dimensional object, comprising:
an operative surface;
at least one supply hopper for depositing layers of powder onto the operative surface;
and
an energy source for emitting at least one energy beam onto the layers of powder,
wherein the supply hopper and energy source are configured such that when a topmost
layer of powder is being deposited onto an underlying layer of powder on the operative
surface:
the direction that the supply hopper is moving in while depositing the topmost layer
is different to the direction that the supply hopper moved in when it deposited the
underlying layer; and
at least one energy beam is emitted onto the topmost layer and at least one further
energy beam is emitted onto the underlying layer simultaneously to melt, fuse or sinter
the topmost and underlying layers simultaneously.
[0008] The apparatus may comprise a levelling means for substantially levelling a layer
of powder deposited on the operative surface.
[0009] The levelling means may comprise a blade that, in use, periodically scrapes an upper
surface of a layer of powder.
[0010] The levelling means may comprise an electrostatic charging means.
[0011] The levelling means may comprise a vibration generation means for applying vibrational
forces to particles comprised in the layer of powder.
[0012] The vibration generation means may comprise a mechanical vibration generator.
[0013] The vibration generation means may comprise an ultra-sonic vibration generator.
[0014] The apparatus may comprise a scanning means for determining a position, velocity
and/or size of one or more particles comprised in the powder when the, or each, particle
is travelling between the supply hopper and the operative surface.
[0015] The scanning means may be adapted to measure the airborne density of the powder.
[0016] The scanning means may be adapted to measure a volume of powder deposited on the
operative surface.
[0017] The scanning means may be adapted to measure a level of the powder deposited on the
operative surface.
[0018] The scanning means may be adapted to measure a topology of a powder layer or part
thereof.
[0019] The scanning means may be adapted to measure a chemical composition of a powder layer
or part thereof.
[0020] The scanning means may be adapted to measure a temperature of each powder layer or
part thereof.
BRIEF DESCRIPTION OF DRAWINGS
[0021] The present invention will now be described, by way of example, with reference to
the accompanying drawings, in which:
Figure 1 is a side schematic view of a conventional 3D printing apparatus known in
the art;
Figure 2 is a side schematic view of a 3D printing apparatus according to a first
embodiment of the invention;
Figure 3 is a further side schematic view of the 3D printing apparatus of Figure 2;
and
Figure 4 is a side schematic view of a 3D printing apparatus according to a second
embodiment of the invention.
DETAILED DESCRIPTION OF THE DRAWINGS
[0022] Referring to Figure 1, there is shown a schematic representation of a conventional
3D printing apparatus 10 known in the art. The apparatus 10 comprises a substrate
12 with an operative surface 14 on which a printed object is to be fabricated by 3D
printing.
[0023] The apparatus 10 further comprises a supply hopper 16 that deposits a single layer
of powder 18 onto the operative surface 14.
[0024] An energy gun 20 (commonly a laser or electron gun) emits an energy beam 22 onto
the layer of powder 18 causing it to melt or sinter selectively to form an individual
layer of the 3D object. The process is repeated to add additional layers and incrementally
build up the object until it is completed.
[0025] Referring to Figure 2, there is shown a schematic representation of a 3D printing
apparatus 24 according to a first embodiment of the present invention.
[0026] The apparatus 24 comprises an operative surface 28, at least one supply hopper 30
for depositing layers 32 of powder 34 onto the operative surface 28 and an energy
source for emitting at least one energy beam 38 onto the layers of powder 32. The
supply hopper 30 and energy source are configured such that when a topmost layer of
powder 40 is being deposited onto an underlying layer of powder 42 on the operative
surface 28, the direction that the supply hopper 30 is moving in while depositing
the topmost layer 40 is different to the direction that the supply hopper 30 moved
in when it deposited the underlying layer 42, and at least one energy beam 38 is emitted
onto the topmost layer 40 and at least one further energy beam 46 is emitted onto
the underlying layer 42 simultaneously to melt, fuse or sinter the topmost and underlying
layers 40,42 to an underlying powder layer or substrate simultaneously.
[0027] More particularly, the apparatus 24 comprises a substrate 26 which forms the operative
surface 28 on which a printed object is to be fabricated by 3D printing. In use, the
supply hopper 30 travels in alternating directions, transverse to the operative surface
28, when depositing each layer of powder. In Figure 2, for example, the apparatus
24 is shown in a state whereby a first layer of powder 42 has been deposited in full
and the supply hopper 30 is actively depositing a second layer of powder 40 overlaying
the first layer 42. The supply hopper 30 is shown currently traveling in the direction
indicated by reference numeral 49 while the second, overlaying layer of powder 40
is being formed.
[0028] In Figure 3, the apparatus 24 is shown in a further state whereby the first and second
layers of powder 42,40 have both been deposited in full and the supply hopper 30 is
actively depositing a third layer of powder 48 immediately above the second layer
40. The supply hopper 30 is shown currently traveling in the direction indicated by
reference numeral 50 while forming the third layer of powder 48, which is different
to the previous direction 49 that it travelled in.
[0029] The supply hopper 30 travels back and forth repeatedly, in an oscillating path, transverse
to the operative surface 28, to incrementally deposit the powder layers 32 onto the
operative surface 28. Preferably, the path followed by the supply hopper 30 is substantially
sinusoidal in at least one dimension transverse to the planar operative surface 28.
It is anticipated, however, that the supply hopper 30 may follow alternative oscillating
paths which are all within scope of the present invention.
[0030] The apparatus 24 further comprises an energy source which, in the first embodiment
of the invention shown in Figures 2 and 3, comprises a first energy gun 36 for emitting
a first energy beam 38 onto the powder layers 32 and a second energy gun 52 for emitting
a second energy beam 46 onto the powder layers 32 to melt or sinter the powder selectively,
thereby forming part of the 3D object.
[0031] The two energy guns 36,52 operate such that the first energy beam 38 is directed
onto, and works on, the topmost layer of powder that is being actively deposited by
the supply hopper 30. Meanwhile, the second energy beam 46 is simultaneously directed
onto, and works on, a layer of powder underlying the topmost layer.
[0032] By way of example, in Figure 2, the first energy beam 38 is shown being directed
onto the second layer of powder 40, which forms the topmost layer of powder that is
being actively deposited by the supply hopper 30. Meanwhile, the second energy beam
46 is shown being directed simultaneously onto the first layer of powder 42 that has
previously been deposited, in full, and is immediately underlying the second layer
of powder 40.
[0033] By way of further example, in Figure 3 the second energy beam 46 is shown being directed
onto the third layer of powder 48 which, at this point in time, forms the topmost
layer of powder being actively deposited by the supply hopper 30. Meanwhile, the first
energy beam 38 is shown being directed, simultaneously, onto the second layer of powder
46 which, at this point in time, has now been deposited in full and forms a layer
underlying the third layer of powder 48.
[0034] The present invention enables two layers of powder to be effectively operated on
by the energy source simultaneously, leading to a corresponding two-fold increase
in printing productivity.
[0035] The energy source used in the apparatus 24 can be any one of a laser beam, a collimated
light beam, a micro-plasma welding arc, a microwave beam, an ultrasonic beam, an electron
beam, a particle beam or other suitable energy beam.
[0036] In embodiments of the invention that make use of electron beam energy sources, the
printing apparatus 24 (including the operative surface 28) may be contained and operated
wholly inside a vacuum chamber to facilitate propagation of the electron beam onto
the layers of powder.
[0037] The effectiveness of the present invention substantially relies on each powder layer
32 being formed in a controlled manner. It is, in particular, important to ensure
that the layers formed have uniform thicknesses and top surfaces that are substantially
level when the powder layers 32 are being worked on by the energy source.
[0038] Due to the nature of powder particles, they often tend to roll across the operative
surface 28 when deposited thereon. This is normally either due to the shape of the
powder particles, e.g. roughly round shaped powder particles that bounce roll on the
operative surface 28 and collide with other powder particles already located thereon,
or the rolling can be caused by the force of the gas feed carrying the powder particles
from the powder supply 30, or the rolling can be caused by gravity by the powder particles
rolling off a "heap" if too many powder particles are deposited at the same position.
[0039] It is also known that the thickness of a layer of powder 32 can be reduced after
the layer has been worked on by the energy source due to, for example, particle shrinkage.
The reduction in thickness may detrimentally affect layers of powder subsequently
deposited by the supply hopper 30 and/or the resultant 3D object that is fabricated.
[0040] The apparatus 24, therefore, additionally comprises a levelling means for substantially
levelling each powder layer 32 during operation.
[0041] In the embodiment disclosed in the Figures, the levelling means comprises a blade
54 that, in use, is periodically scraped over the top surface of a layer of powder
32 in order to modify its thickness, as may be necessary, and to ensure that its top
surface is kept substantially level.
[0042] The blade 54 is controlled using mechanical control means and control electronics
(not shown) driven by software or firmware implementing an algorithm for controlling
the position, speed and orientation of the blade 54.
[0043] The algorithm implemented may cause the blade 54 to operate selectively on any layer
of powder deposited, either in whole or in part, simultaneously with or independently
to the operation of the energy guns 36,52.
[0044] For example, in Figure 2 the blade 54 is shown operating on the first layer of powder
42 that has been deposited in full, while the first and second energy guns 52,36 are
operating, respectively, on the first and second powder layers 42, 40.
[0045] In Figure 3, the blade 54 is shown operating on the second layer of powder 40 that,
at this point in time, has been deposited in full, while the first and second energy
guns 52,36 are operating, respectively, on the second and third powder layers 40,
48.
[0046] Instead of or in addition to the blade 54, the levelling means used by the apparatus
24 may, alternatively, comprise a vibration generation means (not shown) for applying
vibrational forces to a layer of powder 32 that has yet to be melted or sintered by
the energy source. These vibrational forces cause individual particles in the powder
layers 32 to vibrate which, in turn, causes them to become dynamic. The vibrational
forces may be applied selectively to one or more powder layers until the particles
comprised in the, or each, layer form and settle into a desired arrangement.
[0047] The vibration generation means used by the apparatus 24 may be a mechanical vibration
generator or, alternatively, an ultra-sonic vibration generator.
[0048] Further, instead of or in addition to the blade and/or vibration generation means,
the levelling means may comprise an electrostatic charging means which electrostatically
charges both the powder particles and the operative surface 28 with opposed polarities.
[0049] For example, a positive charge can be applied to the operative surface 28 and the
powder particles exiting the supply 30 can be negatively charged. Thus, as the powder
particles exit the supply 30 they are drawn towards the operative surface 28 and,
once contact is made therewith, the powder particles stick in place on the operative
surface 28.
[0050] Advantages of such adhesion is, firstly, that it results in an improved resolution
of the final component as the powder particles can be accurately placed and, secondly,
that working environment within the printing apparatus 24 is improved as there is
less powder particle dust between the supply 30 and the operative surface 28. Further,
it is also possible to control the direction of flow of the electrostatically charged
powder particles using other electrostatic means.
[0051] To enable the apparatus 24 to control the volumetric flow rate and density of airborne
powder 34 emitted from the supply hopper 30 and the levelling means described above,
the apparatus 24, preferably, also comprises a scanning means (not shown).
[0052] The scanning means is, preferably, adapted to determine a position, velocity and/or
size of one or more particles comprised in the powder 34 when the, or each, particle
is travelling from the supply hopper 30 to the operative surface 28.
[0053] The scanning means is, preferably, also adapted to measure the airborne density of
the powder 34.
[0054] The scanning means is, preferably, also adapted to measure a volume of powder deposited
on the operative surface 28.
[0055] The scanning means is, preferably, also adapted to measure a level of the powder
deposited on the operative surface 28.
[0056] The scanning means may make use of an ultra-sonic beam, an electron beam, a laser
or other appropriate scanning or positioning technology.
[0057] Information and data collected using the scanning means is used, in conjunction with
control electronics and software, to determine the volumetric flow rate, direction
and/or velocity of powder emitted from the supply hopper 30 and/or the direction and
intensity of the energy beams 46,38 to optimise fabrication of the part being printed.
[0058] Referring to Figure 4, there is shown a schematic representation of a 3D printing
method and apparatus 24 according to a second embodiment of the present invention.
The embodiment disclosed is identical in all response to the first embodiment disclosed
in Figures 2 and 3 save that the energy source comprises a single energy gun 56 that
is adapted to emit a single energy beam 58 onto an energy splitting means 60.
[0059] The energy beam splitting means 60 splits the single energy beam 58 into two individual
directed energy beams 62,64. The energy beam splitting means 60 operates in conjunction
with a control mechanism (not shown) which ensures that each directed energy beam
62,64 emitted from the energy beam splitting means 60 is directed, simultaneously,
onto a different exposed surface of a layer of powder 32 in the same manner as described
above for the first embodiment of the invention.
1. A printing apparatus (24) for printing a three-dimensional object, comprising:
an operative surface (28);
at least one supply hopper (30) for depositing layers of powder (32) onto the operative
surface (28); and
an energy source for emitting at least one energy beam (38) onto the layers of powder
(32),
characterised in that the supply hopper (30) and energy source are configured such that when a topmost
layer of powder (40) is being deposited onto an underlying layer of powder (42) on
the operative surface (28):
the direction travelled by the supply hopper (30) when depositing the topmost layer
(40) is different to the direction travelled by the supply hopper (30) when depositing
the underlying layer (42); and
at least one energy beam (38) is emitted onto the topmost layer (40) and at least
one further energy beam (46) is emitted onto the underlying layer (42), simultaneously,
to melt, fuse or sinter the topmost (40) and underlying layers (42).
2. The printing apparatus (24) according to claim 1, wherein the apparatus (10) further
comprises a levelling means for substantially levelling a layer of powder (32) deposited
on the operative surface (28).
3. The printing apparatus (24) according to claim 2, wherein the levelling means comprises
a blade (54) that is configured to, in use, periodically scrape an uppermost surface
of a layer of powder (32) on the operative surface (28).
4. The printing apparatus (24) according to claim 2, wherein the levelling means comprises
an electrostatic charging means.
5. The printing apparatus (24) according to claim 2, wherein the levelling means comprises
a vibration generation means for applying vibrational forces to particles comprised
in a layer of powder (32) on the operative surface (28).
6. The printing apparatus (24) according to claim 5, wherein the vibration generation
means comprises a mechanical vibration generator.
7. The printing apparatus (24) according to claim 5, wherein the vibration generation
means comprises an ultra-sonic vibration generator.
8. The printing apparatus (24) according to any one of the preceding claims, wherein
the apparatus further comprises a scanning means for determining a position, velocity
and/or size of one or more particles comprised in the powder (34) when the, or each,
particle is travelling between the supply hopper (30) and the operative surface (28).
9. The printing apparatus (24) according to claim 8, wherein the scanning means is adapted
to measure the airborne density of the powder (34).
10. The printing apparatus (24) according to claim 8 or 9, wherein the scanning means
is adapted to measure a volume of powder (34) deposited on the operative surface (28).
11. The printing apparatus (24) according to any one of claims 8 to 10, wherein the scanning
means is adapted to measure a level of the powder (34) deposited on the operative
surface (28).
12. The printing apparatus (24) according to any one of claims 8 to 11, wherein the scanning
means is adapted to measure a topology of a powder layer (32) or part thereof.
13. The printing apparatus (24) according to any one of claims 8 to 12, wherein the scanning
means is adapted to measure a chemical composition of a powder layer (32) or part
thereof.
14. The printing apparatus (24) according to any one of claims 8 to 13, wherein the scanning
means is adapted to measure a temperature of each powder layer (32) or part thereof.
15. The printing apparatus (24) according to any one of the preceding claims, wherein
the apparatus (24) comprises a first energy gun (36) for emitting a first energy beam
(38) onto the topmost layer and a second energy gun (52) for simultaneously emitting
a second energy beam (46) onto the underlying layer, to melt, fuse or sinter the topmost
and underlying layers.
16. The printing apparatus (24) according to any one of claims 1 to 14, wherein the apparatus
further comprises an energy beam splitting means (60) for splitting the energy beam
into a plurality of separate energy beams and directing at least one energy beam (62)
onto the topmost layer and directing at least one further energy beam (64) onto the
underlying layer, simultaneously, to melt, fuse or sinter the topmost and underlying
layers.
1. Druckvorrichtung (24) zum Drucken eines dreidimensionalen Objekts, umfassend:
eine Wirkfläche (28);
mindestens einen Einlauftrichter (30) zum Absetzen von Schichten aus Pulver (32) auf
der Wirkfläche (28); und
eine Energiequelle zum Emittieren von mindestens einem Energiestrahl (38) auf die
Schichten aus Pulver (32),
dadurch gekennzeichnet, dass der Einlauftrichter (30) und die Energiequelle so ausgestaltet sind, dass, wenn die
oberste Schicht aus Pulver (40) auf einer darunter befindlichen Schicht aus Pulver
(42) auf der Wirkfläche (28) abgesetzt wird:
die von dem Einlauftrichter (30) durchquerte Richtung, wenn die oberste Schicht (40)
abgesetzt wird, sich von der Richtung unterscheidet, die der Einlauftrichter (30)
durchquert, wenn die darunter befindliche Schicht (42) abgesetzt wird; und
simultan mindestens ein Energiestrahl (38) auf die oberste Schicht (40) emittiert
wird und mindestens ein weiterer Energiestrahl (46) auf die darunter befindliche Schicht
(42) emittiert wird, um die oberste (40) und die darunter befindliche Schicht (42)
zu schmelzen, zu verschmelzen oder zu sintern.
2. Druckvorrichtung (24) nach Anspruch 1, wobei die Vorrichtung (10) des Weiteren ein
Nivelliermittel umfasst, um eine Schicht aus Pulver (32), die auf der Wirkfläche (28)
abgesetzt worden ist, im Wesentlichen zu nivellieren.
3. Druckvorrichtung (24) nach Anspruch 2, wobei das Nivelliermittel eine Klinge (54)
umfasst, die ausgestaltet ist, um bei Gebrauch periodisch eine oberste Fläche einer
Schicht aus Pulver (32) auf der Wirkfläche (28) abzuschaben.
4. Druckvorrichtung (24) nach Anspruch 2, wobei das Nivelliermittel ein elektrostatisches
Ladungsmittel umfasst.
5. Druckvorrichtung (24) nach Anspruch 2, wobei das Nivelliermittel ein Vibrationserzeugungsmittel
umfasst, um Vibrationskräfte auf Partikel auszuüben, die in einer Schicht aus Pulver
(32) auf der Wirkfläche (28) enthalten sind.
6. Druckvorrichtung (24) nach Anspruch 5, wobei das Vibrationserzeugungsmittel einen
mechanischen Vibrationserzeuger umfasst.
7. Druckvorrichtung (24) nach Anspruch 5, wobei das Vibrationserzeugungsmittel einen
Ultraschallvibrationserzeuger umfasst.
8. Druckvorrichtung (24) nach einem der vorhergehenden Ansprüche, wobei die Vorrichtung
des Weiteren ein Scanmittel zum Ermitteln einer Position, Geschwindigkeit und/oder
Größe von einem oder mehreren Partikeln umfasst, die in dem Pulver (34) enthalten
sind, wenn das oder jedes Partikel sich zwischen dem Einlauftrichter (30) und der
Wirkfläche (28) bewegt.
9. Druckvorrichtung (24) nach Anspruch 8, wobei das Scanmittel vorgesehen ist, um die
luftgetragene Dichte des Pulvers (34) zu messen.
10. Druckvorrichtung (24) nach Anspruch 8 oder 9, wobei das Scanmittel vorgesehen ist,
um das Volumen des Pulvers (34) zu messen, welches auf der Wirkfläche (28) abgesetzt
wird.
11. Druckvorrichtung (24) nach einem der Ansprüche 8 bis 10, wobei das Scanmittel vorgesehen
ist, um ein Niveau des Pulvers (34) zu messen, das auf der Wirkfläche (28) abgesetzt
wird.
12. Druckvorrichtung (24) nach einem der Ansprüche 8 bis 11, wobei das Scanmittel vorgesehen
ist, um eine Topologie einer Pulverschicht (32) oder eines Teiles derselben zu messen.
13. Druckvorrichtung (24) nach einem der Ansprüche 8 bis 12, wobei das Scanmittel vorgesehen
ist, um eine chemische Zusammensetzung der Pulverschicht (32) oder eines Teiles davon
zu messen.
14. Druckvorrichtung (24) nach einem der Ansprüche 8 bis 13, wobei das Scanmittel vorgesehen
ist, um eine Temperatur von jeder Pulverschicht (32) oder einem Teil davon zu messen.
15. Druckvorrichtung (24) nach einem der vorhergehenden Ansprüche, wobei die Vorrichtung
(24) eine erste Energiekanone (36) zum Emittieren eines ersten Energiestrahls (38)
auf die oberste Schicht und eine zweite Energiekanone (52) zum simultanen Emittieren
eines zweiten Energiestrahls (46) auf die darunter befindliche Schicht umfasst, um
die oberste und darunter befindliche Schichten zu schmelzen, zu verschmelzen oder
zu sintern.
16. Druckvorrichtung (24) nach einem der Ansprüche 1 bis 14, wobei die Vorrichtung des
Weiteren ein Energiestrahl-Splittermittel (60) umfasst, um den Energiestrahl in eine
Vielzahl separater Energiestrahle zu splitten, und simultan mindestens einen Energiestrahl
(62) auf die oberste Schicht zu richten und mindestens einen weiteren Energiestrahl
(64) auf die darunter befindliche Schicht zu richten, um die oberste und darunter
befindlichen Schichten zu schmelzen, zu verschmelzen oder zu sintern.
1. Appareil d'impression (24) pour imprimer un objet tridimensionnel comprenant :
une surface fonctionnelle (28) ;
au moins une trémie d'alimentation (30) pour déposer des couches de poudre (32) sur
la surface fonctionnelle (28) ; et
une source d'énergie pour émettre au moins un faisceau d'énergie (38) sur les couches
de poudre (32),
caractérisé en ce que la trémie d'alimentation (30) et la source d'énergie sont configurées de telle sorte
que, lorsque la couche la plus haute de poudre (40) est déposée sur une couche sous-jacente
de poudre (42) sur la surface fonctionnelle (28) :
la direction de déplacement de la trémie d'alimentation (30) lors du dépôt de la couche
la plus haute (40) soit différente de la direction de déplacement de la trémie d'alimentation
(30) lors du dépôt de la couche sous-jacente (42) ; et
au moins un faisceau d'énergie (38) soit émis sur la couche la plus haute (40) et
au moins un faisceau d'énergie supplémentaire (46) soit émis sur la couche sous-jacente
(42), en même temps, pour faire fondre, fusionner ou fritter la couche la plus haute
(40) et la couche sous-jacente (42).
2. Appareil d'impression (24) selon la revendication 1, l'appareil (10) comprenant en
outre un moyen de nivellement pour niveler sensiblement une couche de poudre (32)
déposée sur la surface fonctionnelle (28).
3. Appareil d'impression (24) selon la revendication 2, dans lequel le moyen de nivellement
comprend une lame (54) qui est configurée pour, lors de l'utilisation, racler périodiquement
une surface supérieure d'une couche de poudre (32) sur la surface fonctionnelle (28).
4. Appareil d'impression (24) selon la revendication 2, dans lequel le moyen de nivellement
comprend un moyen de charge électrostatique.
5. Appareil d'impression (24) selon la revendication 2, dans lequel le moyen de nivellement
comprend un moyen de génération de vibrations pour appliquer des forces vibratoires
à des particules incluses dans une couche de poudre (32) sur la surface fonctionnelle
(28).
6. Appareil d'impression (24) selon la revendication 5, dans lequel le moyen de génération
de vibrations comprend un générateur de vibrations mécaniques.
7. Appareil d'impression (24) selon la revendication 5, dans lequel le moyen de génération
de vibrations comprend un générateur de vibrations ultrasonores.
8. Appareil d'impression (24) selon l'une quelconque des revendications précédentes,
l'appareil comprenant en outre un moyen de balayage pour déterminer une position,
une vitesse et/ou une taille d'une ou de plusieurs particules incluses dans la poudre
(34) lorsque la particule, ou chaque particule, se déplace entre la trémie d'alimentation
(30) et la surface fonctionnelle (28) .
9. Appareil d'impression (24) selon la revendication 8, dans lequel le moyen de balayage
est conçu pour mesurer la densité de la poudre (34) en suspension dans l'air.
10. Appareil d'impression (24) selon la revendication 8 ou 9, dans lequel le moyen de
balayage est conçu pour mesurer un volume de poudre (34) déposé sur la surface fonctionnelle
(28).
11. Appareil d'impression (24) selon l'une quelconque des revendications 8 à 10, dans
lequel le moyen de balayage est conçu pour mesurer un niveau de la poudre (34) déposée
sur la surface fonctionnelle (28).
12. Appareil d'impression (24) selon l'une quelconque des revendications 8 à 11, dans
lequel le moyen de balayage est conçu pour mesurer une topologie d'une couche de poudre
(32) ou d'une partie de celle-ci.
13. Appareil d'impression (24) selon l'une quelconque des revendications 8 à 12, dans
lequel le moyen de balayage est conçu pour mesurer une composition chimique d'une
couche de poudre (32) ou d'une partie de celle-ci.
14. Appareil d'impression (24) selon l'une quelconque des revendications 8 à 13, dans
lequel le moyen de balayage est conçu pour mesurer une température de chaque couche
de poudre (32) ou d'une partie de celle-ci.
15. Appareil d'impression (24) selon l'une quelconque des revendications précédentes,
l'appareil (24) comprenant un premier pistolet à énergie (36) pour émettre un premier
faisceau d'énergie (38) sur la couche la plus haute et un second pistolet à énergie
(52) pour émettre en même temps un second faisceau d'énergie (46) sur la couche sous-jacente,
pour faire fondre, fusionner ou fritter la couche la plus haute et la couche sous-jacente.
16. Appareil d'impression (24) selon l'une quelconque des revendications 1 à 14, l'appareil
comprenant en outre un moyen de division de faisceau d'énergie (60) pour diviser le
faisceau d'énergie en une pluralité de faisceaux d'énergie distincts et pour diriger
au moins un faisceau d'énergie (62) sur la couche la plus haute et pour diriger au
moins un faisceau d'énergie supplémentaire (64) sur la couche sous-jacente, en même
temps, pour faire fondre, fusionner ou fritter la couche la plus haute et la couche
sous-jacente.